The present invention relates to a suspension for supporting a magnetic head slider of a magnetic disc drive or photomagnetic disc drive incorporated in an information processing apparatus, such as a personal computer, portable computer, etc.
A hard disc drive (HDD) includes a carriage that can turn around a shaft. The carriage is turned around the shaft by means of a positioning motor. The carriage is provided with an arm, a suspension on the distal end portion of the arm, a head portion attached to the suspension, etc. The head portion is provided with a magnetic head slider that is situated in a position such that it can face a recording surface (track) of a disc, a transducer held on the slider, etc. When the disc rotates at high speed, the slider is slightly lifted from the disc surface, whereupon an air bearing is formed between the disc and the slider.
FIG. 13 shows an example of a conventional suspension 7. The suspension 7 includes a load beam 11 formed of a precision thin plate spring, a flexure 12 formed of a very thin plate spring that is fixed to the distal end portion of the beam 11, a base plate 13 fixed to the proximal portion of the load beam 11, etc. A magnetic head slider 10 is mounted on a tongue portion 12a that is formed on the flexure 12. The flexure 12 has rather low stiffness such that the slider 10 that is slightly lifted from the disc can flexibly change its posture.
A hemispherical protrusion 15 is formed on the distal end portion of the load beam 11 so as to project toward the flexure 12 in the thickness direction thereof. The top of the protrusion 15 can engage the tongue portion 12a of the flexure 12. Thus, a head portion 8 can make three-dimensional displacements, such as pitching and rolling, around the protrusion 15. Since the protrusion 15 is depressed on the backside of the load beam 11, it is called a dimple in the art. In some cases, the protrusion 15 may be provided on the flexure 12 in place of the load beam 11.
If the conventional suspension 7 is subjected to an intolerable shock, the head portion 8 behaves unstably, so that the head portion 8 and the disc may be damaged in some cases. Thus, when the suspension 7 is shocked, the distal end portion of the load beam 11 may spring up, or the head portion 8 may pitch or roll. Accordingly, a corner portion of the head portion 8 runs against the disc surface, possibly resulting in damage to the head portion 8 or the disc. This drawback is promoted by dimple separation or separation between the flexure 12 and the protrusion 15, in particular.
In U.S. Pat. No. 5,333,085, 5,771,136 or 5,838,517, a limiter mechanism is described and proposed as means for restraining the dimple separation. In conventional limiter mechanisms, partial bent portions on a load beam, for example, are opposed in the bending direction of a flexure so that the flexure engages the bent portions when the displacement of the flexure reaches its tolerance limit. Alternatively, partial bent portions on the flexure are opposed to the load beam so that they engage the load beam to restrain the movement of the flexure when the displacement of the flexure reaches its tolerance limit. These conventional limiter mechanisms make the distal end portion of the suspension wider.
As shown in FIG. 14, the suspension 7 moves around a shaft 2a of a carriage 2 in the direction of arrow M over a disc 9. When the suspension 7 is moved to the inner peripheral side of the disc 9, a fixed clearance C should be secured between a distal end portion 7a of the suspension and a hub ring 17. With use of the conventional limiter mechanisms that increase the width of the suspension end portion 7a, therefore, the data area on the disc 9 is reduced inevitably.
Accordingly, the object of the present invention is to provide a suspension for disc drive, enjoying high shock resistance and capable of effectively restraining the movement of a flexure without increasing the width of its distal end portion.
In order to achieve the above object, a suspension according to the present invention comprises a flexure for supporting a magnetic head slider, a load beam for supporting the flexure, and a limiter mechanism for regulating the movement of the flexure, the limiter mechanism including a checking portion formed of part of the load beam extending rearward from the distal end of the flexure and facing the flexure across a gap in the thickness direction of the flexure.
According to the suspension of the invention constructed in this manner, the limiter mechanism that includes the checking portion on the load beam can restrain the posture of the flexure from being substantially changed by a shock and prevent dimple separation without increasing the stiffness of the flexure or changing the shape of the flexure. The distal end portion of the suspension with the limiter mechanism according to the invention cannot be wider than that of the conventional suspension.
According to the invention, the flexure includes a tongue portion provided with a magnetic head slider and a pair of outrigger portions situated individually on the opposite sides of the tongue portion, and the limiter mechanism is provided with a nipping portion including a first checking portion facing one surface of the flexure so as to restrain the tongue portion and the outrigger portions from bending in the thickness direction thereof and a second checking portion facing the other surface of the flexure. According to the suspension of the invention constructed in this manner, the limiter mechanism can regulate the displacements of the tongue portion and the outrigger portions that are shocked, thereby more effectively restraining the movement of the flexure in the pitching and rolling directions.
According to the invention, the limiter mechanism includes an extension portion for enlarging the area of opposition between the load beam and the flexure. The extension portion can more effectively restrain the movement of the shocked flexure.
According to the invention, moreover, the limiter mechanism includes a checking portion formed of part of the flexure extending rearward from the distal end of the load beam and facing the load beam across a gap in the thickness direction of the load beam. According to the suspension of the invention constructed in this manner, the limiter mechanism that includes the checking portion on the flexure can restrain the posture of the flexure from being substantially changed by a shock without increasing the stiffness of the flexure or changing the shape of the flexure.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.